1. Field of the Invention
The present invention relates, in general, to a parking system for storing a plurality of vehicles in a limited area, and more particularly, to a palletless rack-type parking for quickly, precisely and safely taking a vehicle into and/or taking it out of the parking space system using a stacker crane operable in more than two axial directions to a rack unit having a plurality of parking spaces without a separate vehicle loading pallet.
2. Description of the Prior Art
In recent years, a rapid increase of vehicles causes the absolute lacking phenomena of parking places, so it becomes serious social problems of raising the difficulty of parking following by the traffic congestion and the environmental pollution. Particularly, the problem of parking places becomes more serious in very busy midtowns due to limited parking places, so it leads to frequent illegal parking, which blocks a traffic flow resulting in the terrible traffic jams.
In an effort to solve such problems of illegal parking and a shortage of parking places in busy cities, there have been attempted a variety of solutions, for example, strengthening of parking regulations and enacting of ordinances which oblige building owners to establish parking places in or around their buildings. However, the expansion of parking places couldn""t help having a limitation due to the difficult of securing lands in busy cities.
Therefore, a variety of schemes have been studied in search of a better solution for effectively parking many vehicles on limited areas. As a result of such studies, several parking systems have been proposed and widely used to store vehicles in floors in parking spaces using a mechanical drive unit.
Such conventional parking systems are generally classified into several types such as a circulation-type system, a puzzle-type system, an elevator-type system, etc., in accordance with a drive system. Each of the circulation-type and puzzle-type systems must store a vehicle on its exclusive parking pallet defining a parking space thereon and follow the movement of a plurality of vehicles at the same time of loading or unloading one vehicle into or it out of a parking space, so the demand for such systems falls off nowadays. In place of the circulation-type and puzzle-type systems, elevator-type parking systems have been most widely used, which can simply enter a vehicle into a designated parking space or delivery it therefrom.
An example of a conventional elevator-type parking system is disclosed in Korean Patent No. 0271061 which comprises an elevator for carrying a vehicle loaded pallet to a position of an empty parking space of racks formed in floors and a traction unit for moving the vehicle from the elevator into the empty parking space in a horizontal direction to store it. Of course, the delivery of a vehicle out of the parking space is performed in the reverse order to the entering of the vehicle.
However, the parking system must have a complex configuration because of requiring additional pallets and transact units except the elevator. During the operating of the system, a loading of the system is increased by a weight of the pallets, so it is undesirable in respect that a lot of power and much time are required for the transportation of the vehicle.
In particular, after the loading of the vehicle into a designated parking space of a rack, if some vehicle-free or empty pallets are placed on the parking places, the elevator is moved to the empty parking space to pull out the empty pallet therefrom and then ready for another parking operation at a carrying-in position to be on standby. During being on standby, the elevator carries the empty pallet loaded thereon to be put on another pallet-free parking space according to a delivery control signal and then again moved from the standby position to a target parking space to store another vehicle. As a result, the parking system using such movable pallets undesirably needs a relative longer time for loading vehicles into or unloading them out of the parking spaces of racks.
In order to overcome these and those problems, there has been proposed a palletless rack-type parking system for loading or unloading vehicles into or out of parking spaces of multistory racks without requiring additional pallets. Examples of palletless rack-type parking system are referred to International Laid-open Publication No. WO87/02405 entitled xe2x80x9cA Vertical Storage Apparatus and Control Method Thereofxe2x80x9d and Japanese Patent Laid-open Publication No. Heisei 5-52058 entitled xe2x80x9cA Stacker Crane-type Parking Garage.
The vertical storage apparatus disclosed in WO 87/02405 comprises a single rack unit including an elevation space and multi-storied storage racks provided on at least one side out of the left side, right side, front side and rear side of the lift space. The rack comprises a plurality of storage forks normally arranged on every story thereof to form two rows spaced apart in a regular interval from each another. The elevation space defined between the storage spaces comprises a pair of elevation forks mounted to be moved up and down therein to carry vehicles in a vertical direction. The storage fork reciprocates between a storage space and the elevation space by a drive unit (not shown) in a manner to be moved toward or away from a position above or under the fork bars of the elevation forks according to the guidance of a horizontal guide beam of the rack. The elevation fork comprises a pair of elevation forks faced to each other, fork bars of which are vertically passed through between fork bars of the storage fork to be placed at a loading/unloading position in the elevation space, without interfering with the fork bars of the storage fork.
In a storage operation, the elevation fork loaded with a vehicle on its fork bars is first moved upward in the elevation space to a desired position higher than that of a target empty storage fork. The target empty storage fork is horizontally moved inward into the elevation space by means of the drive unit to a loading position under the fork bars of the elevation fork. The elevation fork is moved downward to cross the fork bars of the storage fork in order to load the vehicle onto the storage fork. The storage fork is returned by means of the drive unit to its original position, so that vehicle is entered into a storage space of the rack.
However, the vertical storage apparatus free of a pallet has problems in that the drive unit must be provided to operate each storage fork, independently, and the moving distance of the elevation fork is relatively longer, because the elevation fork passes through or cross the storage fork, vertically, during a loading or unloading operation.
Furthermore, the target storage fork must be horizontally moved to a loading or unloading position under or above an elevation fork 2 without causing any interference between the vehicle and any one of the storage and elevation forks. For it, a substantial travel of the elevation fork is a sum of adding an operational allowance to two heights of the storage fork and the elevation fork, which takes a relative longer time for the storage and delivery of the vehicle, so the vertical storage apparatus has a limitation to the reduction of time taken during a loading or unloading operation.
The loading structure for stacker crane-type parking garages described in Japanese Patent Laid-open Publication No. Heisei. 5-52058 comprises two racks installed on a support surface to be spaced apart at an interval from each other and a stacker crane (not shown) mounted between the racks to enable a lift fork to be moved up and down with being loaded with a vehicle. Multiple cantilever support bars are provided on the right and left shelf members of each rack to form a storage space inside horizontal support beams. The lift fork includes a plurality of arm bars provided on both sides of a body of the stacker crane to cross the support bars without any interference during being lifted or lowered in a protruded state.
In a loading operation, the lift fork loaded with the vehicle is first moved upward in an elevation space to a desired position higher than that of the support bar and then horizontally to be entered into a target empty storage space of the racks. Thereafter, the lift fork is moved downward to cross the support bar of the rack. During the downward movement of the lift fork, the arm bars pass through the spaces between the support bars without any interference to load the vehicle onto the support bars. The lift fork is, thereafter, laterally moved from the position under the support bars to a position inside the elevation space, prior to being moved to a standby position where another vehicle is loaded on the lift fork.
However, the loading structure is constructed such that the lift fork passes through the support bars 6 from above its upper portion to below its lower portion thereby to return to its original position, so it has a limitation to the time reduction in loading the vehicle into or unloading it out of the storage space due to a relatively longer traveling distance. Therefore, a substantial travel of the lift fork is a sum of adding an allowance for entering into/retreating from the rack to two heights of the support fork and the lift fork. It has a limitation to the shortening of a vertical traveling distance of the lift fork.
According to the present invention, in order to resolve these and those problems, an object of the present invention is to provide a palletless rack-type parking system for quickly, precisely and safely taking a vehicle into and/or taking it out of the parking space system using a stacker crane operable in more than two axial directions to a rack unit having a plurality of parking spaces without a separate vehicle loading pallet.
In order to accomplish the object of the present invention, a palletless rack-type parking system comprises:
a plurality of multistory racks each having a plurality of parking spaces in a lattice form and arranged on a support surface to be spaced apart from each another at a regular interval to form vertical spaces between them;
a plurality of storage fork bars each including a first projection tab projected from a predetermined portion of a lower surface thereof to have a predetermined height and horizontally mounted on an upper surface of a first support beam in a regular interval through the first projection tap to cross the support beam in a right angle, at least one end of which is projected longer from the support beam of the rack in a beam form;
a transporting fork including a plurality of transporting fork bars each with a second projection tap projected from a predetermined portion of a lower surface thereof to have a predetermined height, in which the transporting fork bar is not higher than that of the storage fork bar, and arranged in a regular interval in parallel to each another to be alternately positioned between the storage fork bars, and a second support beam arranged to cross the storage fork bar in a right angle and for supporting the second projecting tap facing its lower surface; and
a stacker crane installed in each vertical space between two neighboring racks and operable in more than two-axial directions of leftward, rightward, upward and downward with the transporting fork being mounted thereon, in which the transporting fork laterally approaches the storage fork bars and the transporting fork bars enter into, moves up and down and retreats from the storage fork with being alternately overlapped between the storage fork bars.
According to the present invention, it is preferable that the upper surface of the transporting fork bar is positioned higher or lower than the upper surface of the storage fork bar by a predetermined level without any interference between them, when the transporting fork laterally approaches or withdraws from the storage fork bar.
It is more preferable that the heights of the storage fork bar and the transporting fork bar are equal to each other and the heights of their first and second projection tap are equal to each other, the height of the projection taps is determined to be at least larger than a level difference to be kept between the upper surfaces of the transporting fork bar and the storage fork bar, when the transporting fork laterally approaches or withdraws from the storage fork bar.
Accordingly, when the transporting fork approaches or withdraws out of the storage fork bar, the present invention enables any one of fork bars to be lifted up to at least minimum allowance gap relative to the other. It is possible for a vehicle to be quickly and safely taken into or taken out of a parking space without causing any interference between the fork and its relative fork bar and also excludes the use of a separate pallet.